A Product Line of
Diodes Incorporated
PAM8302L
2.5W FILTERLESS CLASS-D MONO AUDIO AMPLIFIER
Description
Pin Assignments
The PAM8302L is a 2.5W Class-D mono audio amplifier. Its low
THD+N offers high-quality sound reproduction.
The PAM8302L uses a filterless design that avoids the use of lowpass filters. This new design allows the amplifier to directly drive a
speaker, making it cheap and compact. The new design allows the
amplifier to be more affordable and take less PCB area.
The PAM8302L uses less power than the Class-AB amplifiers. The
use of this product can help optimize battery life; it is ideal for portable
applications.
The PAM8302L is available in MSOP-8 and DFN3x3-8 packages.
Features
•
Support 2.0V to 5.5V Supply Voltage Range
•
2.5W Output at 10% THD with a 4Ω Load and 5V Power Supply
•
Filterless, Low Quiescent Current and Low EMI
•
High Efficiency up to 88%
•
Superior Low Noise
•
Short Circuit Protection
•
Thermal Shutdown
•
Few External Components to Save Space and Cost
•
MSOP-8 and DFN3x3 Packages Available
•
Pb-Free Packages
Applications
•
PMP/MP4
•
GPS
•
Portable Speakers
•
Walkie Talkie
•
Handsfree phones/Speaker Phones
•
Cellular Phones
Typical Applications Circuit
PAM8302L
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PAM8302L
Pin Descriptions
Pin Number
1
2
3
4
5
6
7
8
Pin Name
SD
NC
IN+
INVO+
VDD
GND
VO-
Function
Shutdown Terminal (active low)
No Connection
Positive Differential Input
Negative Differential Input
Positive BTL Output
Analog Power Supply
Ground
Negative BTL Output
Functional Block Diagram
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability. All voltages are with respect to ground.
Parameter
Supply Voltage at No Input Signal
Input Voltage
Maximum Junction Temperature
Storage Temperature
Soldering Temperature
Rating
6.0
Unit
-0.3 to VDD +0.3
150
-65 to +150
300, 5sec
V
°C
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Parameter
Suppy Voltage Range
Operation Temperature Range
Junction Temperature Range
PAM8302L
Document number: DSxxxxx Rev. 1 - 0
Rating
2.0 to 5.5
-40 to +85
-40 to +125
Unit
V
°C
°C
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Thermal Information
Parameter
Package
MSOP-8
DFN3x3-8
MSOP-8
DFN3x3-8
MSOP-8
DFN3x3-8
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation @ TA = +25°C
Symbol
θJC
θJA
PD
Max
75
20
180
50
550
2000
Unit
°C/W
°C/W
mW
Electrical Characteristics (@TA = +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, COUT = 10µF, L = 4.7µH, unless otherwise specified.)
Parameter
Supply Voltage Range
Symbol
Quiescent Current
IQ
Shutdown Current
ISHDN
Output Power
Peak Efficiency
Total Harmonic Distortion Plus Noise
Test Conditions
PO
η
THD+N
Min
No Load
4
VSHDN = 0V
f = 1kHz, RL = 4Ω,
THD+N = 10%
VDD = 5V
2.25
2.50
VDD = 3.6V
1.10
1.25
f = 1kHz, RL = 4Ω,
THD+N = 1%
VDD = 5V
1.80
2.00
VDD = 3.6V
0.86
0.95
f = 1kHz, RL = 8Ω,
THD+N = 10%
VDD = 5V
1.35
1.50
VDD = 3.6V
0.72
0.80
f = 1kHz, RL = 8Ω,
THD+N = 1%
VDD = 5V
1.15
1.30
VDD = 3.6V
0.6
0.65
f = 1kHz
Power Supply Ripple Rejection
Dynamic Range
Signal to Noise Ratio
Noise
Oscillator Frequency
Drain-Source On-State Resistance
DYN
SNR
VN
SHDN Input High
VSH
SHDN Input Low
VSL
OTP
OTH
Over Temperature Protection
Over Temperature Hysterisis
PAM8302L
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mA
1
µA
W
88
0.35
RL = 8Ω, PO = 0.5W, f = 1kHz
0.45
0.50
RL = 4Ω, PO = 0.1W, f = 1kHz
0.35
0.40
IDS = 100mA
0.45
24.0
25.5
45
50
dB
85
75
90
80
180
120
dB
dB
P MOSFET
N MOSFET
120
dB
300
200
µV
250
300
kHz
0.45
0.20
0.50
0.25
Ω
0.4
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%
0.40
1.2
Junction Temperautre
%
22.5
200
fOSC
RDS(ON)
V
8
85
No Inputs, f = 1kHz, VPP = 200mV
f = 20 to 20kHz
f = 20 to 20kHz
No A-Weighting
A-Weighting
Units
5.5
0.30
GV
PSRR
Max
RL = 8Ω, PO = 0.1W, f = 1kHz
RL = 4Ω, PO = 0.5W, f = 1kHz
Gain
Typ
2.5
VDD
135
30
V
°C
°C
November 2012
© Diodes Incorporated
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Diodes Incorporated
PAM8302L
Typical Performance Characteristics (@TA = +25°C, unless otherwise specified.)
PAM8302L
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PAM8302L
Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.)
PAM8302L
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PAM8302L
Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.)
PAM8302L
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Application Information
Test Setup for Performance Testing
Notes:
1. The Audio Precision (AP) AUX-0025 low pass filter is necessary for every Class-D amplifier measurement with AP analyzer.
2. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Maximum Gain
As shown in block diagram (Page 2), the PAM8302L has two internal amplifier stages. The first stage's gain is externally con figurable, while the
second stage's is internally fixed. The closedloop gain of the first stage is set by selecting the ratio of RF to RI while the second stage's gain is
fixed at 2x.The output of amplifier one serves as the input to amplifier two, thus the two amplifiers produce signals identical in magnitude, but
different in phase by 180°. Consequently, the differential gain for the IC is
A =20*log [2*(RF/RI)]
The PAM8302L sets maximum R =80kΩ, minimum RI =10kΩ, so the maximum closed-gain is 24dB.
Input Capacitor (CI)
Intypical application, an input capacitor, CI is required to allow the amplifier to bias input signals to a proper DC level for optimum operation. In
this case, CI and the minimum input impedance RI (10k internal) form a high pass filter with a corner frequeny determind by the following
equation:
fC =
1
2ΠR I CI
It is important to choose the value of CI as it directly affects low frequency performance of the circuit, for example, when an application requires a
flat bass response as loas as 100Hz,. Equation is reconfigured as follows:
CI =
1
2ΠR I f I
As the input reisitance is varible, for the CI value of 0.16µF, one should actually choose the CI within the range of 0.1µF to 0.22µF. A further
consideration for this capacitor is the leakage path from the input source through the input network (RI, RF, CI) to the load. This leakage current
creates a DC offset voltage at the input to the amplifier that reduces useful headroom, especially in high gain application. For this reason, a low
leakage tantalum or ceramic capacitor is the best choice. When a polarized capacitior is used, the positive side of the capacitor should face the
amplifier input in most applications as the DC level is held at VDD/2, which is likely higher than the source DC level. Please note that it is
important to confirm the capacitor polarity in the application.
PAM8302L
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Application Information (cont.)
Power Supply Decoupling (CS)
The PAM8302L is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and
PSRR as low as possible. Power supply decoupling affects low frequency response. Optimum decoupling is achieved by using two capacitors of
different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a
good low equivalent-series-resistance (ESR) ceramic capacitor, typicall 1.0µF is good, placing it as close as possilbe to the device VDD terminal.
For filtering lower frequency noise signals, capacitor of 10µF or larger, closely located to near the audio power amplifier is recommended.
Shutdown Operation
In order to reduce shutdown power consumption, the PAM8302L contains shutdown circuitry for turn to turn off the amplifier. This shutdown
feature turns the amplifier off when a logic low is apllied on the SD pin. By switching the shutdown pin over to GND, the PAM8302L supply
current draw will be minimized inidle mode.
For the best power on/off pop performance, the amplifier should be set in the shutdown mode prior to power on/off operation.
Under Voltage Lock-Out (UVLO)
The PAM8302L incorporates circuitry to detect low on or off voltage. When the supply voltage drops to 2.1V or below, the PAM8302L goes into a
state of shutdown, and the device comes out of its shutdown state to normal operation by reset the power supply or SD pin.
How to Reduce EMI (Electro Magnetic Interference)
A simple solution is to put an additional capacitor 1000μF at power supply terminal for power line coupling if the traces from amplifier to speakers
are short (< 20CM). Most applications require a ferrite bead filter as shown at Figure 1. The ferrite filter depresses EMI of around 1MHz and
higher. When selecting a ferrite bead, choose one with high impedance at high frequencies and low impedance at low frequencies.
Figure 1. Ferrite Bead Filter to Reduce EMI
PAM8302L
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Ordering Information
Part Number
PAM8302LASCR
PAM8302LAYCR
Package Type
MSOP-8
DFN3x3-8
Standard Package
2500 Units/Tape&Reel
3000 Units/Tape&Reel
Marking Information
PAM8302L
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Package Outline Dimensions (All dimensions in mm.)
MSOP-8
PAM8302L
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Package Outline Dimensions (cont.) (All dimensions in mm.)
DFN3x3-8
PAM8302L
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